Sulfur-containing carboxylic acid esters



Patented Jan. 3, 1950 I'SUERUR-CONTAIN IN G CARBOXYLIC ACID ESTERS John David Kendall and HarryDerek Edwards, 'Ilford, England, assignors to lilford Limited,

Ilford, England, a British company No Drawing. Application August 2, 1946, Serial No. 687,939. .In Great Britain August 17,1945

8- Claims. (Cl. 260327) '1 2 This invention relates to the production of new The various compounds are lettered (a) to (Z) organic compounds which are-valuable intermefor convenience in-subsequent reference herein. 'diat'es'for the pr-oductionof organic compounds In connection with the above reactions it of commercial utility. should be pointed outthat since the reactions are Various attempts have been made in the past effected using thealkali metal salt of'the original to effect reaction between carbon disulphide and compounds (a), (e) and (i) it is 'probablethat -compounds containing reactive methylene'groups, in all the 'formulaewhere a sulphur atom is and some measure of success in certain instances shown as linked toa simple hydrogen atom, that has been obtained. Examples are the processes hydrogen atom will be replaced by an atom of the described by Apitzsch in Berichte, "volume 38, alkali metal. The intermediate stages (19) or page 2888, and volume-41,;page 4028, by Wenzel (f) or (y) and (7') .or (k) .areincluded for the in Berichte, volume 33, page 2041, and volume sake of clarity, but it will be understood that p es 10431045,'afid5i1'1*BiitiSh a e there is no necessity to isolate .such intermedi- 3201. The processesdescribed in these publicat tions, however are of limited application-and the 1.", If t js d n lkylating agent which per. products, am d oyh se pr methods are mits it, the groupsiRt in compounds ('d),'( iL) and entirely different .fromthose with whichthe pres- (1) may link uptoform a rin compound. ent.in 0niS e e For example, if the alkylating agent is chlorc d fifl the Present lnventlon, acetic ethyl ester the reaction proceeds as foleach a hydrocarbon group, preferably an alkyl l 1110 O C-GlI-G (221331 ,ganic compouds are preparedbyreacting carbon 20 lows; disulphide with the .dry.alka1i:me,ta1 derivative ofa compound ofthe general formula:

where Q represents any of the groupings =0 COQR2, coat or CN (i..e. an acid ester,

acyl or nitrile .grouping) and. R R and R are (41) group, and reacting the vproduct with an alkyl 000cm,

salt or alkylester. R1000 vIt is importantto the ,producton of a high yield .of the productsthat thereaction with carbon disulphide shouldbe.efiectedinamedium substan- Q -SO 2 -tially .-free..of water .or. any. other .hydroxylic sol- "vent. l-Iowever, .the .presence in the reaction 05 I mixture of .a small ,quantity of ethyl alcohol,

while usually reducing the. yield, in some cases CH-G,OOO2H5| tends toincrease the rate .of the reaction. \CH2 .(JO (s) The series.of.reactions is believed to be as follows. (In these formulae R4 represents an alkyl' 40 In e above .fo m la the mtermedlate ps or substituted alkyigmup.) in the formationof-the dimercaptal have been omitted. The precise nature of theproduct (r) :o 11-00011 "ROG-G11 ,GOOR NG-OH (300R G C 2 3 2- 1 r 1 .or (3) 1s uncertain, but it will be-appreclated that i l l these-compounds"are/structurally isomeric.

'Further, the Ri -groups maybe connected to 3-0300031 form a single di-valent grouping linking .the two sulphur atoms: such products being obtained by A g the use as alkylatingagents'of di-salts or di-esters, H SH eng. alkyleneidihalidessuch as ethylene dibromide or trimethylene ,dibromide.

'01" I01 01' Thev products of this invention are valuable ino *NO-C-COOR mooc 96 H (k) 1 termediates in the production of other organic Q compounds. For example, by hydrolysis of a s11 "SH .sH s11 s11 SH compound of type (d) where the R4 groups are l methylgroups there isobtained the compound:

,ll HOOC OH=C (m) U and this on dry distillation breaks down to form ketene dimercaptal:

/SCH: CHFC\ SCH:

Similarly compounds of type (h) may be converted to compounds of type (m) and. thence to compounds of type (n).

In the case of compounds of type (1) where the R4 groups constitute a single divalent grouping the effect of hydrolysis is to cause the compound to break down as follows:

I; II 8/ \IS CN-CH The reaction with carbon disulphide can conveniently be efiected with the compounds in suspension in ether though other inert solvents can be used. As alkali-metal, metallic sodium is preferred as being the most convenient to use. The alkylation may be efiected, for example, with methyl, ethyl or higher alkyl halides and the iodides are particularly suitable. Other alkylating agents which may be used are dialkyl sulphates, e. g. dimethyl sulphate or diethyl sulphate, alkyl p-toluene sulphonates, e. g. methyl or ethyl p-toluene sulphonate, alkylene dihalides such as ethylene dibromide and trimethylene dibromide. As already indicated the alkyl group of the alkylating agent may be substituted so that other alkylating agents which may be used are chloracetic esters and benzyl halides or sulphates.

The following specific examples serve to illustrate the invention:

EXAMPLE 1 Preparation of a compound of the Formula (d) where R1 and R2 are ethyl groups and R4 is a methyl group One molecular equivalent of powdered sodium was covered with anhydrous ethyl ether. Half a molecular equivalent of diethyl malonate was added slowly, the mixture stirred for ten hours and then allowed to stand for 12 hours. Half a molecular equivalent of carbon disulphide was added at room temperature and the mixture stirred for 15 hours. It was then allowed to stand for days, refluxed for 5 hours, and allowed to cool. One molecular equivalent of methyl iodide was then added slowly with stirring and gentle warming. The reaction mixture was then refluxed for 3 hours, allowed to stand for 24 hours and filtered. The filtrate was concentrated by evaporation of ether and the residue distilled twice at mm. pressure. The product had a boiling point at 196 C./ 15 mm., and was a light yellow oil.

EXAMPLE 2 Alternative preparation of the product of Example 1 One molecular equivalent of powdered sodium was covered with anhydrous ethyl ether and one molecular equivalent of ethyl alcohol was added. The mixture was stirred for 8 hours, allowed to stand for 12 hours, half a molecular equivalent of diethyl malonate added and then stirred for 4 hours. A thick gelatinous precipitate was formed. Half a molecular equivalent of carbon disulphide was then added and the mixture stirred for one hour and allowed to stand for 12 hours. One molecular equivalent of methyl iodide was then added with stirring at room temperature and the mixture allowed to stand for 36 hours. The resulting solution was filtered, the filtrate concentrated and then distilled at 20 mm. pressure. The product had a boiling point of 204 C. at 20 mm. pressure.

The compound of the Formula (m) may be prepared from the foregoing product by the following method.

One molecular equivalent of the compound produced as above was added to 2%: molecular equivalents of potassium hydroxide (15% alcoholic solution) and allowed to stand for 3 hours. The precipitated salt was filtered ofi, dissolved in water and acidified with 10% hydrochloric acid. A yellow oil was precipitated, carbon dioxide was evolved and the yellow oil hardened to a white solid. This was recrystallised from ethyl alcohol solution yielding the required product as colourless crystals, M. Pt. 197 C. By dry distillation, at 10 mm. pressure, these crystals yielded ketene dimercaptal boiling at C. at 10 mm. pressure.

EXAMPLE 3 Preparation of the compound of the Formula (h) where R1 is an ethyl group and R4 is a methyl group One molecular equivalent of powdered sodium was covered with anhydrous ethyl ether, one molecular equivalent of ethyl acetoacetate was added slowly, and the mixture stirred for 5 hours and left standing overnight. One molecular equivalent of carbon disulphide was then added, and the mixture stirred. One molecular equivalent of ethyl alcohol was then added and the mixture refluxed for 5 hours and allowed to stand for 6 days. During this period the sodium ethyl acetoacetate appeared to pass into solution. A yellow precipitate was formed and this was filtered off and suspended in fresh anhydrous ether. A slight excess over half a molecular equivalent of methyl iodide was added, the mixture refluxed for 4 hours, allowed to stand for 12 hours and then filtered. The filtrate was concentrated, and the residue distilled at 15 mm. pressure. It boiled at 164 C. The distilled product was then recrystallised from petroleum ether (6080 boiling range) solution as colourless crystals, M. Pt. 56 C. An increased yield may be obtained by using a larger quantity of methyl iodide, for example up to two molecular equivalents.

EXAMPLE 4 Preparation of the compound of the Formula (I) where R1 is an ethyl group and R4 is a methyl group One molecular equivalent of powdered sodium was covered with anhydrous ether, one molecular equivalent of ethyl cyanacetate was added and the mixture refluxed for 3 days. One molecular equivalent of carbon disulphide was then stirred in and the reaction mixture allowed to stand for 10 days. Methyl iodide (two molecular equivalents) was then added and the mixture refluxed for 3 days and then allowed to stand for 10 days. The solution was then filtered and the filtrate concentrated and distilled at 30 mm. pressure. The product distilled at 215 C. On recrystallisation from ethyl alcohol it was obtained as colourless crystals, M. Pt. 57 C.

5 EXAMPLES.

Preparation oj the compound of theFormula' (r) or-('s)' The additiomof carbondisulphide to sodio ethyl malonate was efiected as in Example 2 using the same proportions of reagents. Then, instead of using methyl iodide, onez molecular equivalent of ethyl chloracetate .was added! and the. mixture stirred for-,2 hoursandthen refiuxed;for. .1 hour. A precipitate formed on cooling and this was filtered oil (A). The filtrate was concentrated and distilled'at 15 mm. pressure; A- fraction boiling at 158-460. C. proved to :be ethanetnicare box-ylic ester, and anotheriraction; boiling .a-t- 220-260 set solid. This latter. productfiBb -was washed with ethyl alcohol. It had a melting point of 87 C.

The precipitate A was washed with water and ethyl alcohol and then ground with dilute hydrochloric acid, filtered anchthe residue recrystallised from. ethylalcohol. This. productv also melted: at 87:". C.. 'andwaslidentical. with the productBbut in much greater yield, and was the required compound.

EXAMPLE 6 Preparation ojthe. compound of the. Formula (d); where R1. and R2 are ethyl groupsand the R4 groups area single dimethglene group, Le...

I I UH -CH Two-molecular equivalents of powdered sodium were coveredlwithlanh-yd-rous. diethyl ether. One molecular equivalent of" 'diethyl malonate was added slowly,- Withstiming; and-the mixture allowed to stand for 48 hours. One molecular equivalent or carbon disulphide was then added at room temperature, with stirring, andthe mixture left to-=sta-nd for72'hoursr One molecular equivalent of ethylene dibromide was then added andthe mixture allowedto stand for. 8;.W8Bk. It was then gently-refluxed for 36 hours andfiltered. The filtrate'wassconcentrated by evaporation of ether and distilled at. 2.5 mm. pressure. The desired compound distilled ..with .a boiling point of 202 C; at 2.5 mm. pressure. It" was a bright yellow oil. lwhiclnsolidified...on standing.

The foregoing product, on.-.hydrolysis.by tneatment with 15 alcoholic potassium hydroxide solution in the cold for 48 hours yielded a precipitate which, on washing with alcohol, dissolution in water and acidification with hydrochloric acid, yielded a precipitate of the compound having the formula:

HOOCCH=C SCH7 which had a melting point of 150 0.

EXAMPLE 7 Preparation of the compound of the Formula (l) where R1 and R4 are ethyl groups Two molecular equivalents of powdered sodium were covered with anhydrous ether and one '2 minut'es'with 5 N alcoholicpotassium hydroxide,

molecular equivalent of ethyl cyanacetate was and the mixtme-rallowedztolstandjor .hours with occasional.vigorousirstirring: Twmmolecuflar equivalents of ethyl iodide .were then slowly added to the warmed solution and the mixture was keptwarm f-or 24 hours 1 and then allowed: to stand for-1-20'--hours.- The -resulting solution was filtered The fi-ltrate -was set aside andthe resi: due was coveredwith ethe-rand treated with one molecular equivalent of "ethyl: alcohol. and two molecular equivalents oflethyl iodide; A vigorous reaction took place. The mixturewas allowed to-stand for =24 hours; and-then poured on to cracked icein i an atmosphere of carbon dioxide. The-ether solution was washed with water and dried over anhydrous-sodium su-lphate. It was then' filtered, concentrated and distilled at 1.5 mm. pressureyielding' the desired product as a pale yellow oil, B. Pt.t. C. vat.1.5 mm. pressure. The original filtrate set aside earlier, on distillationyielded"'a-small amount of" the same product;

EXAMPLE 8 reparationof the compound 'of Formula: (bl whereRr'is an-ethyf group and"R4- is a benzg l group The reaction procedure-oflilxampletl was. fol? lowed except. that benzylwchloride-was used in-. stead .of,-ethyl- -iodide... Theoriginallyobtained etherial. solution was filteredandthe. residue washed. to a yield the product. as..- large colourless crystals, Pt..8& C. on recrystallisation from ethyl alcohol solution, The filtrate, on concentration, hardened to-yieltf-an oil-which, on treatment. with. ethyl alcohol, =gaveaef-urthergyieldr of the product. '1

EXAMPLE '9- 7 Preparation of: thecompound; otFormula (t) where Rz is; ethyl. ancl'Rrv trimethylene The reaction" procedure of Example 'l'was followedexc'ept -that the equivalent amount of trimethylene dibromide was used instead of ethyl iodide. The etherialwsolutioncwwfias treated as in Example 8 givinga substantial yield of the product from. theresidue; after; filtration .and a smaller yield'from the filtrate; The product. had a .melting point of 92 CI This product,.on'hydrolysis by refluxing for yielded a solid product which on purification had a;melting'pointof2155C; with decomposition. It had the Formula ('u) where R4 is a trimethylene group. On distillation of this product in vacuo an oil was obtainedLwl-iichisolidified.tin long needle clusters, M. Pt. 32 C. This had the Formula (11) where R; is trimethylene.

What we claim is:

1. Process for the production of organic compounds which comprises reacting carbon disulfide with a dry alkali-metal derivative of a reactive methylene compound of the general formula:

where Q is selected from the group consisting of COOR2, COR3 and CN, and R1, R2, and Rs are hydrocarbon groups, under substantially anhydrous conditions in an inert medium and reacting the resulting reaction product with an alkylating agent taken from the group consisting of alkyl halides, dialkyl sulfates, alkyl-p-toluene sulfonates, alkylene dihalides, benzyl halides, benzyl sulfates and chloracetic acid alkyl esters.

2. Process for the production of organic comequivalent of carbon disulphide was then added 75 DO dS which mp es e g carbon disulfide with a dry sodium derivative of a reactive methyl-1 ene compound of the general formula:

Q-CHz-COORi where Q is selected from the group consisting of --COOR2, CORs and CN and R1, R2 and R3 are hydrocarbon groups, under anhydrous conditions in a diethyl ether medium and reacting the resulting reaction product with an alkylating agent taken from the group consisting of alkyl 25 halides, dialkyl sulfates, alkyl-p-toluene sulfonates, alkylene dihalides, benzyl halides, benzyl sulfates and chloracetic acid alkyl esters.

4. Process for the production of organic compounds which comprises reacting carbon disulfide with a dry sodium derivative of a reactive methylene compound of the general formula:

where Q is selected from the group consisting of COORz, CORa and CN and R1, R2 and R3 are hydrocarbon groups, under anhydrous conditions in a diethyl ether medium and reacting the resulting reaction product with an alkyl halide.

5. Process for the production of organic compounds which comprises reacting carbon disulfide with a dry sodium derivative of a reactive methylene compound of the general formula:

where Q is selected from the group consisting of COORz, COR: and CN and R1, R2 and R3 are hydrocarbon groups, under anhydrous conditions in a diethyl ether medium and reacting the resulting reaction product with an alkylene dihalide.

6. The process which comprises reacting carbon bisulfide with the dry sodium derivative of the formula:

in an anhydrous diethyl ether medium and reacting the resulting reaction product with methyl iodide and recovering the compound of the formula:

7. The process which comprises reacting carbon 10 bisulfide with the dry sodium derivative of the formula:

in an anhydrous diethyl ether medium and react- ]5 ing the resulting reaction product with methyl iodide and recovering the compound of the formula:

8. The process which comprises reacting carbon bisulfide with the dry sodium derivative of the formula:

C2H5OOC-CH2COOC2H5 in an anhydrous diethyl ether medium and reacting the resulting reaction product with ethylene dibromide and recovering the compound of the 30 formula:

C2H5O O CCC 0 O 02H! II S S ()Hz (5 Hz JOHN DAVm KENDALL. HARRY DEREK EDWARDS.

d 0 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 45 Number Name Date 2,193,415 Coltof Mar. 12, 1940 FOREIGN PATENTS A Number Country Date 60 549,202 Great Britain Nov. 11, 1942 OTHER REFERENCES Chemical Abstracts 27: 2149-8 (1933). 

1. PROCESS FOR THE PRODUCTION OF ORGANIC COMPOUNDS WHICH COMPRISES REACTING CARBON DISULFIED WITH A DRY ALKALI-METAL DERIVATIVE OF A REACTIVE METHYLENE COMPOUND OF THE GENERAL FORMULA: 